Field of the Invention
The present invention relates to a control apparatus for internal combustion engines that controls a throttle opening to be applied to calculate control parameters for internal combustion engines.
Description of the Related Art
In recent years, an engine control method referred to as “torque-based control” is widely used. The torque-based control uses an engine output shaft torque as a driving force request value from a driver or a vehicle and controls the generation torque of the engine using this torque as an indicator. The torque-based control determines the target torque of the engine based on the amount of operation of the accelerator pedal by the driver, controls the opening of the throttle valve so that the target flow rate of intake air for enabling the generation of the target torque is sucked to the engine, adjusts the output of the engine to the target torque by controlling the amount of fuel injection and the ignition timing according to the actual flow rate of intake air, and achieves the travel performance requested by the driver.
In the control apparatus for an engine that controls the throttle opening by driving the actuator provided in tandem for the throttle valve of the engine to achieve the target flow rate of intake air corresponding to the target torque of an engine, there is proposed a section that obtains the target opening area of the throttle valve by applying the target flow rate of intake air, the ratio of pressures before and after the throttle valve, the opening area of the throttle valve, and the like to the flow rate expression of the basic throttle type flow meter, and controls the actuator connected to the throttle valve to obtain the throttle opening that achieves the target opening area of the throttle valve.
In addition, for example, Japanese Patent No. 4237214 (PTL 1) proposes the technique that focuses on the fact that the correlation between the effective opening area and the throttle opening prepared in advance depends on variations in the throttle valve, various kinds of sensors, and the like, and learning-corrects the correlation between the effective opening area and the throttle opening to match the actual flow rate of intake air with the target flow rate of intake air, so that the actual flow rate of intake air accurately matches the target flow rate of intake air.
In addition, for example, Japanese Patent No. 5328967 (PTL 2) proposes the technique that uses the learning of the correlation between the throttle opening and the effective opening area and calculates the actual cylinder flow rate of intake air based on the learned correlation from the time of transient change until the temperature of the interior of the exhaust pipe from the exhaust valve to the catalyst converges.
[PTL 1] Japanese Patent No. 4237214
[PTL 2] Japanese Patent No. 5328967
However, since throttle opening learning improves the control accuracy by subdividing the learning region for each driving zone in the technique proposed in PTL 1 or PTL 2, learning may not be completed only by general travel in the region that is difficult to drive, such as, for example, the full-open region. Accordingly, when a learning incompletion region by such a driving pattern is left, the control accuracy is not improved even if the throttle opening learning value is considered in throttle control across a learning incompletion region.